.TH tcptracer 8  "2020-02-20" "USER COMMANDS"
.SH NAME
tcptracer \- Trace TCP established connections. Uses Linux eBPF/bcc.
.SH SYNOPSIS
.B tcptracer [\-h] [\-v] [\-p PID] [\-N NETNS] [\-\-cgroupmap MAPPATH] [--mntnsmap MAPPATH]
.SH DESCRIPTION
This tool traces established TCP connections that open and close while tracing,
and prints a line of output per connect, accept and close events. This includes
the type of event, PID, IP addresses and ports.

This tool works by using kernel dynamic tracing, and will need to be updated if
the kernel implementation changes. Only established TCP connections are traced,
so it is expected that the overhead of this tool is rather low.

Since this uses BPF, only the root user can use this tool.
.SH REQUIREMENTS
CONFIG_BPF and bcc.
.SH OPTIONS
.TP
\-h
Print usage message.
.TP
\-v
Print full lines, with long event type names and network namespace numbers.
.TP
\-p PID
Trace this process ID only (filtered in-kernel).
.TP
\-N NETNS
Trace this network namespace only (filtered in-kernel).
.TP
\-\-cgroupmap MAPPATH
Trace cgroups in this BPF map only (filtered in-kernel).
.TP
\-\-mntnsmap  MAPPATH
Trace mount namespaces in the map (filtered in-kernel).
.SH EXAMPLES
.TP
Trace all TCP established connections:
#
.B tcptracer
.TP
Trace all TCP established connections with verbose lines:
#
.B tcptracer \-v
.TP
Trace PID 181 only:
#
.B tcptracer \-p 181
.TP
Trace connections in network namespace 4026531969 only:
#
.B tcptracer \-N 4026531969
.TP
Trace a set of cgroups only (see special_filtering.md from bcc sources for more details):
#
.B tcptracer \-\-cgroupmap /sys/fs/bpf/test01
.SH FIELDS
.TP
TYPE
Type of event. In non-verbose mode: C for connect, A for accept, X for close.
.TP
PID
Process ID
.TP
COMM
Process name
.TP
IP
IP address family (4 or 6)
.TP
SADDR
Source IP address.
.TP
DADDR
Destination IP address.
.TP
SPORT
Source port.
.TP
DPORT
Destination port.
.TP
NETNS
Network namespace where the event originated.
.SH OVERHEAD
This traces the kernel inet accept function, and the TCP connect, close,
and set state functions. However, it only prints information for connections
that are established, so it shouldn't have a huge overhead.

As always, test and understand this tools overhead for your types of workloads
before production use.
.SH SOURCE
This is from bcc.
.IP
https://github.com/iovisor/bcc
.PP
Also look in the bcc distribution for a companion _examples.txt file containing
example usage, output, and commentary for this tool.
.SH OS
Linux
.SH STABILITY
Unstable - in development.
.SH AUTHOR
Iago López Galeiras
.SH SEE ALSO
tcpaccept(8), tcpconnect(8), tcptop(8), tcplife(8)
